SnO2 nanoparticles based highly sensitive gas sensor for detection of C4F7N: A new eco-friendly gas insulating medium.

As a novel eco-friendly gas insulation medium, perfluoroisobutyronitrile (C4F7N) has been utilized in various gas insulated equipment. Considering the biological toxicity of C4F7N, it is of great engineering significance to develop highly sensitive sensors for leakage detection scenarios. Herein, we fabricated the first SnO2 nanoparticles based highly sensitive C4F7N gas sensor that realized a superior response of 65.01% within 21 s for 50 ppm C4F7N exposure and a detection limit of 0.25 ppm. Meanwhile, successive response-recovery tests were performed to confirm its durability and stability. We also explored the sensing mechanism of SnO2 nanoparticles towards C4F7N and explained the superior sensing performance compared with other gases based on the density functional theory. It was found that the O vacancy demonstrates strong interaction with the -CN group in C4F7N that promotes the detection response, which was also confirmed by sensing experiments for SnO2 with different O vacancy density. We believe this paper provides convincing support for lowering the potential operation risk brought by C4F7N in electrical engineering and the application scenarios of SnO2 based gas sensors.